NATURE 



[November 21, 1901 



The discussion of animal courtship and its psycho- 

 logical analysis constitute one of the most interesting 

 parts of the work. The author's conclusions will, it is 

 believed, be fully accepted by those who follow the 

 Darwinian theory of sexual selection. The more e.\- 

 uberant phraseology of previous writers on the same sub- 

 ject was prooably never intended to convey anything very 

 different from the conduct and climax of courtship as 

 here described. But it has required the assistance of 

 one trained both as psychologist and as zoologist to 

 expound the subject so that misapprehension is well- 

 nigh impossible. The author's twofold capacity in deal- 

 ing with subjects which require to be looked at from very 

 different points of view, as expressed in the title of this 

 review, renders, not only the discussion of courtship, 

 but the whole work, of great value to students in two 

 very different yet closely related fields of knowledge. 



E. B. P. 



CELLULOSE. 

 Researches on Cellulose from 1895-1900. By Cross and 

 Bevan. Pp. vii -I- 180. (London : Longmans, Green 

 and Co.) Price 6j'. net. 



VEGETABLE substances or products of vegetable 

 origin have always had a peculiar fascination to 

 chemists, not only because of the light which may be 

 thrown on general chemical science, should methods of 

 synthesis be discovered, but often because, as was the 

 case with alizarm and more recently with indigo, huge 

 industrial applications may be the outcome of this branch 

 of research. Further, researches are often conducted 

 with the hope that we may be enabled to reveal some of 

 the hidden secrets of nature, as, for example, how the 

 elements which are assimilated by plants in the form of 

 the simplest of compounds become ultimately converted 

 into some of the most complex combinations known to 

 chemists. 



In "Researches on Cellulose," by Cross andBevan,we are 

 dealing with a class of substances which may be said to 

 form the structural basis of all natural organic substances. 

 A very large amount of research has been carried out 

 with the object of ascertaining the molecular configuration 

 of the celluloses, but it cannot be said, up to the present, 

 to have thrown very much light upon the ultimate 

 structure of these substances. If the researches on 

 cellulose have not been very fruitful in this direction, they 

 have, on the other hand, been of enormous industrial im- 

 portance. A very much larger number of industries are 

 concerned with "cellulose" in one form or another than 

 those who have not studied the subject are probably 

 aware. We have only to think of the colossal scale upon 

 which paper is manufactured and the employment of 

 nitrocelluloses in the manufacture of smokeless powder 

 to realise the far-reaching applications of cellulose. 



The authors state in their preface that the present 

 volume is intended as a supplement to the work which 

 they published six years ago. The book is more or less 

 in the form of abstracts of researches which have been 

 published since 1895, but it also contains results of the 

 authors' own investigations which have not previously 

 been recorded. The chemistry of cellulose has attracted 

 considerable attention abroad, but in England, with a 

 NO. 1673, VOL. 65] 



few • exceptions, it has been almost neglected. Messrs. 

 Cross and Bevan call attention to this neglect, and remark 

 that : — 



" To the matter of the present volume, excluding our 

 own investigations, there are but two contributions from 

 English laboratories. We invite the younger genera- 

 tion of chemists to measure the probability of finding 

 a working career in connection with the cellulose 

 industry." 



Considering the enormous importance, the vast extent 

 and the almost unlimited possibilities of the cellulose 

 industry, we trust that this invitation will meet with a 

 hearty response. It is remarkable that in text-books on 

 chemistry, with the exception of technical works — which 

 in this country are few and far between — the subject of 

 cellulose takes a very back-seat. But perhaps we can 

 hardly blame the authors of such works, whose intention, 

 generally speaking, is to teach the theory of organic 

 chemistry. When very little is known about the theory 

 of the subject, it is not unnatural that very little should 

 be said about it. 



The book commences with a general introduction, in 

 which the authors reply to some of the criticisms of 

 their previous work. They then explain in detail the 

 plan of the book, and consider the following classification 

 to be the most natural. 



" Cellulose is in the first instance a s/rucfurc, and the 

 anatomical relationships supply a certain basis of classi- 

 fication. Next, it is known to us and is defined by the 

 negative characteristics of resistance to hydrolytic 

 actions and oxidations. These are dealt with in order of 

 their intensity. Next we have the more positive defini- 

 tion by ultimate products of hydrolysis, so far as they are 

 known, which discloses more particularly the presence 

 of a greater or less proportion of furfural-yielding 

 groups.' 



Until more definite knowledge of the ultimate struc- 

 ture of the various celluloses is known, this method of 

 classification seems to be about the best. 



The section on cellulose esters is extremely good, the 

 paragraphs on the cellulose benzoates, which the authors 

 have prepared by first treating fibrous cellulose (cotton) 

 with a 10 per cent, solution of caustic soda and then with 

 benzoyl chloride, being exceptionally interesting. It is 

 rather interesting to note, by the way, that the dibenz- 

 oate is devoid of all structure, and is therefore readily 

 recognised from the fibrous monobenzoate. 



Under cellulose acetates the authors correct the state- 

 ment made in their previous work that "on boiling cotton 

 with acetic anhydride and sodium acetate, no reaction 

 occurs." .\t the boiling point of the anhydride an ester 

 is obtained, although without any apparent structural 

 alteration of the fibre. Under esters is also included 

 inorganic esters — the nitro-esters, which are of such im- 

 portance in the manufacture of cordite, ballistite, " smoke- 

 less powders," &c. 



The articles on lustra-cellulose or artificial silk will 

 interest many, but the authors protest against the term 

 artificial silk, and suggest that the term ^'■lustra-cellulose" 

 should be employed. Considering the manner in which 

 the term " artificial " is so often misused, we quite agree. 

 Inform the public that an article is artificial and they at 

 once brand it as "false"' or as a "substitute." In the 



